Procedure and system for optical network survival against multiple failures

Abstract

The procedure comprises using a pre-planned path restoration scheme for computing in advance, or pre-calculating, recovery paths for recovering failed working paths, and particularly comprises pre-calculating a set of recovery paths for each working path linking an origin node with a destination node, and simultaneously using the recovery paths of the set of recovery paths to try to communicate the origin node with the destination node, in case of one or more failures have been produced in the working path. The system is arranged for pre-calculating a set of recovery paths for each working path and simultaneously using them to recover a working path failure, and is apt for implementing the procedure.

1 - 20 . (canceled) 
     
     
         21 . A procedure for optical network survival against multiple failures, comprising using a pre-planned path restoration scheme for computing in advance, or pre-calculating, recovery paths for recovering failed working paths, wherein in case of single or multiple failures have been produced in each of said working paths it comprises:
 pre-calculating a set of recovery paths for each working path linking an origin node (O) with a destination node (D),   simultaneously using the recovery paths of said set of recovery paths to try to communicate, said origin node (O) with said destination node (D), by means of simultaneously sending different request recovery messages through said recovery paths; and   selecting at said destination node (D), the recovery paths to be used depending on said different request recovery messages sent.   
     
     
         22 . The procedure as per  claim 21 , wherein said paths of said set of recovery paths are at least three in number, such that at least one of the recovery paths is valid in case of a double link failure. 
     
     
         23 . The procedure as per  claim 21 , comprising detecting a working Label Switched Path, or LSP, failure at said origin node (O). 
     
     
         24 . The procedure as per  claim 23 , wherein said failure detection is performed by means of loss of signal or loss of quality indications. 
     
     
         25 . The procedure as per  claim 21 , wherein the pre-calculation of each of said recovery paths takes into account route, wavelength and optical parameters for the transponder, for each working path. 
     
     
         26 . The procedure as per  claim 21 , wherein the number of recovery paths of said set of recovery paths is configurable, such as the number of recovery paths is configured according to the desired level of protection, wherein the higher the number of recovery paths, the higher the level of protection. 
     
     
         27 . The procedure as per  claim 21 , wherein said request recovery messages differ from each other by including different recovery path identifiers, and include respective path fields indicating the route embraced by the respective recovery path. 
     
     
         28 . The procedure as per  claim 26 , comprising receiving, said destination node (D), at least one of said request recovery messages, and answering by sending back, to the origin node (O), a response recovery message through the route indicated in the path field of the received request recovery message. 
     
     
         29 . The procedure as per  claim 28 , comprising receiving, said destination node (D), at least two of said request recovery messages, and answering by sending back, to the origin node (O), a response recovery message through the route indicated in the path field of a selected one of the at least two received request recovery messages. 
     
     
         30 . The procedure as per  claim 29 , comprising selecting from said at least two received request recovery messages, by said destination node (D), the one which has arrived first. 
     
     
         31 . The procedure as per  claim 28 , comprising reserving resources, needed for the transmission through the recovery path through which the response recovery message is circulating, said resources reservation being done in a backwards sequence through the nodes included in the route of said recovery path up to the origin node (O), by using the information included in the response recovery message. 
     
     
         32 . The procedure as per  claim 31 , comprising receiving, by said origin node (O), said response recovery message, and establishing as working path the recovery path whose route is indicated in the path field of the response recovery message. 
     
     
         33 . The procedure as per  claim 21 , wherein said paths are Label Switched Paths, or LSPs. 
     
     
         34 . A system for optical network survival against multiple failures, comprising:
 detection means for detecting a failure in a working path linking an origin node with a destination node;   processing means for, following a restoration scheme, computing in advance, or pre-calculating, recovery paths for recovering failed working paths;   control means, connected to said detection means and said processing means, for building a recovery path upon the detection of a working path failure;   wherein said system is characterised in that said processing means are arranged for pre-calculating a set of recovery paths for each working path, and in that said control means are arranged for simultaneously using the recovery paths of said set of recovery paths to try to establish communications between said origin node and said destination node, in case of at least a failure has been produced in each of said working path.   
     
     
         35 . The system as per  claim 34 , wherein said processing means are included in a multipath computation module ( 101 ) and said detection and control means are included in an optical node survivability controller module ( 105 ), said modules being bidirectionally communicated there between through corresponding communication sub-modules ( 102 ,  106 ), and being included or associated to said origin node. 
     
     
         36 . The system as per  claim 35 , wherein said control means are intended for requesting to said processing means, through said communication sub-modules ( 102 ,  106 ), recovery paths for a working path, said processing means being intended for sending, also through said communication sub-modules ( 102 ,  106 ), said set of recovery paths to the control means upon receiving said request. 
     
     
         37 . The system as per  claim 36 , wherein said optical node survivability controller module ( 105 ) comprises a recovery path memory sub-module ( 107 ), communicated with said communications sub-module ( 106 ) for at least receiving and storing said set of recovery paths, and with said control means for at least receiving and storing adjustment data calculated by the latter with respect of each of the recovery paths, in order to build them. 
     
     
         38 . The system as per  claim 37 , wherein said optical node survivability controller module ( 105 ) also comprises a signalling sub-module ( 110 ) communicated with the control means for sending through the recovery paths corresponding request recovery messages to the destination node and for receiving at least one response recovery message there from. 
     
     
         39 . The system as per  claim 38 , comprising second processing means included or associated to said destination node for processing the request recovery messages received and sending back said response recovery message towards the origin node through one of said recovery paths. 
     
     
         40 . System as per  claim 39 , wherein it implements the method as per  claim 21 .